Answer:
See prove of the identity below
Step-by-step explanation:
Recall that the following difference can be factored out as:
Now we look at the right side of the equal sign, and recall the identity that relates the sine of a double angle 2A with an expression in terms of the tan(A):
and similarly, the tangent of the double angle "2A" can be written as:
We can then combine the two expressions on the right using the common denominator: :
And we have proved the identity since the right hand side becomes exactly equal to the left hand side of the equal sign.